Welcome to my J.A.M. (Just Ask Mike) Session, a weekly column where I answer your basic electrical questions. If you’re a newbie who’s never plugged in a shore power cord (or ask – what’s a shore power cord?), or wonder why your daughter’s hair dryer keeps tripping the circuit breaker, this column is for you. Send your questions to Mike Sokol at mike (at) noshockzone.org with the subject line – JAM. Today Mike discusses how much amperage kitchen appliances use.
Here’s what I saw the other day on the Thor ACE Motorhome Facebook Group that I think is worthy commenting on here. Yes, it’s about those high-amperage electrical kitchen appliances and why they can be trouble in a 30-amp RV.
Yes, I know that air frying is a healthy alternative to deep frying in oil. Yes, I know it tastes great. And, yes, this could help feed the kids and grandkids with all kinds of healthy and tasty snacks while camping.
So what’s the problem?
Here’s the amount of power available for 20-, 30- and 50-amp shore power connections. You can see that the humble 20-amp “Edison” outlet in your house has a maximum available current of 20 amperes, which works out to 2,400 watts of power. That’s because amps x volts = watts. If we know the voltage (120 volts) and the wattage of an appliance, to find the amperage we simply calculate watts / volts = amps. So a 1,200-watt appliance divided by 120 volts equals 10 amps, as in 1,200 watts / 120 volts = 10 amps. Easy, eh?
What about running my waffle iron or hair dryer or Ninja Air Fryer?
Well, many of those appliances have a wattage rating listed online, but sometimes finding the amperage draw is a bit tricky, but here’s how to do it. As near as I can tell, this Ninja Air Fryer draws 1,750 watts which is 14.5 amperes of current. As above, just divide the appliance’s listed wattage by 120 volts to find out just how much amperage it draws.
- 1,800 watts / 120 volts = 15 amps
- 1,500 watts / 120 = 12.5 amps
- 1,200 watts / 120 = 10 amps
- 1,000 watts / 120 = 8.33 amps
- 800 watts / 120 = 6.66 amps
- 600 watts / 120 = 5 amps
Now all you have to do is add them up to make sure you don’t go over your allotted 30 amps of pedestal current. Let me throw in three more numbers you need to be aware of.
- Electric water heater element = 1,500 watts (12.5 amps)
- Lithium battery 60-amp charger = 1,000 watts (8.33 amps)
- Lithium battery 80-amp charger = 1,300 watts (10.83 amps)
- Rooftop A/C unit (13,500 BTU) = 1,600 watts (13.3 amps)
- Rooftop A/C compressor has a 50-amp (or more) starting surge
I think that Green Acres had the right idea back in their 1965’s SitCom where they marked all the extension cords with numbers and knew what combinations would work, and what would probably blow a fuse. I think a chart showing you what combinations you should avoid is a great idea.
So is there a workaround?
Well, sort of kind of. While you can’t get more energy from the 30-amp pedestal outlet, if the campground has a 20/30/50-amp pedestal, it’s likely that the 20- and 30-amp outlets are on separate poles. So the 30-amp outlet would be on hot-leg 1, and the 20-amp outlet would be on hot-leg 2.
If that’s the case, then you could simply run a separate heavy-duty, 12- gauge extension cord from the 20-amp pedestal outlet and plug it directly into your Ninja fryer. This is actually allowed by code, while connecting a second shore power cord directly into your RV is a code violation.
Now, if this trips the 30-amp breaker feeding the pedestal, then there’s not enough amperage at the pedestal to use the 30-amp and 20-amp outlets at the same time. In any event, don’t be tempted to try one of the so-called 45-amp adapters to plug a 50-amp shore power cord into both 30- and 20-amp outlets. Because there has to be a GFCI outlet on any outside 20-amp outlet, it will instantly trip. So don’t waste your money and time on it.
OK, everyone. Remember that electricity is a useful and powerful force, so we all need to pay attention to safety precautions while using it.
Let’s play safe out there….
Mike Sokol is an electrical and professional sound expert with 50+ years in the industry. His excellent book RV Electrical Safety is available at Amazon.com. For more info on Mike’s qualifications as an electrical expert, click here.
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